[EM] SARC definition improvement

[Markus Schulze]

Dear Mike,

suppose that candidate X is the expected winner if every
voter votes sincerely. Then -to my opinion- an "offensive"
strategy is a strategy that a given voter uses to make a
candidate win who is prefered by this voter (due to his
sincere preferences) to candidate X. And -to my opinion-
a "defensive" strategy is a strategy that a given voter
uses to make not a candidate win who is not prefered by
this voter (due to his sincere preferences) to candidate X.
In other words: A "defensive" strategy is a counterstrategy;
a "defensive" strategy is a reaction to a predicted
strategy of another voter.

You wrote (24 Aug 2000):
> Your sincere ranking is ABC
>
> 100 voters: ABC
> 99 voters: BAC
>
> Without you, A wins.
>
> Then you show lup, and, believing that B needs your vote
> against C, you vote BAC. Now B wins. You've defeated your
> favorite by voting an undefeated strategy.

The additional voter believes that candidate C would be
elected if every voter voted sincerely. The voter votes
insincerely to make a candidate win who is prefered by this
voter (due to his sincere preferences) to the expected
winner C. Therefore I consider this strategy to be "offensive."
Therefore I don't consider the fact that in this example
this voter actually worsens the result of the elections
(due to his sincere preferences) to be a problem of Borda.

Markus Schulze
schulze at sol.physik.tu-berlin.de
schulze at math.tu-berlin.de
markusschulze at planet-interkom.de